Here is a great post by Qwer on mercury and how it inpairs healthy metabolic functions:

I believe heavy metals are very important, at least for a certain group of people with candida, or even just for bad bacterias in the gut in general.

-Candida causes the methylation of mercury: methylmercury is easily absorbed, while inorganic (plain) mercury has a lot less chance of being absorbed, and it can not cross the blood-brain barrier. It can eventually be methylated by the body if it's in the blood though.
-Mercury accumulates mainly in the liver, the brain and the intestines.
-Good bacterias seem to play a role in mercury detoxification, as antibiotics decrease mercury excretion.
-Candida is one of this though organisms that resist the most to mercury. In the presence of mercury, it will have a lot more chance to survive than our friendly
bacterias.
-Mercury impairs the enzyme (DPP-IV) that digest correctly the protein gluten in wheat and casein in milk. Because it strongly binds to sulfur, it also impairs many enzymes related to sulfur.
-Mercury might make bacterias more resistant to antibiotics.
It might also have a protecting influence for virii and parasites, making them more resistant.

So even in the case that mercury is not the main culprit, chances are that those with candida have a bigger mercury burden.

I personally believe in Chlorella for detoxification, unfortunalety they say everywhere that it takes quite while to feel the effects. I've been taking 20 grams a day for 3 weeks, and they say it can takes 3-4 months... At my dosage I hope it takes less time. Feels like marketing, although I trust that guy Mercola (mercola.com) who also believe in this.

Other heavy metals such as lead and cadmium have a synergetic effect with mercury.